Asymmetric Dual-Mode Ionization Chamber for Modality Switching
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Solution Overview
Problem
Conventional radiation therapy systems require extensive calibration and downtime when switching between different treatment modalities, such as conventional radiotherapy and flash radiotherapy, due to the need to exchange and recalibrate the ionization chamber measurement system.
Innovation Solution
An asymmetric dual-mode ionization system with a high-voltage supply, switch matrix, and ion charge measurement circuit that allows for automatic switching between two modes by adjusting the high-voltage potential and active volumes within the ionization chamber to accommodate different radiation rates, enabling continuous operation without recalibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the ionization chamber measurement system is exchanged and recalibrated when switching between treatment modalities, then measurement accuracy is maintained, but system availability and productivity deteriorate due to extended downtime
Solution Approach 1:
The ionization chamber measurement system is designed with multiple ionization chambers that can be selectively activated based on the treatment modality. Each ionization chamber is configured with specific electrode arrangements and active volumes optimized for different radiation types and dose rates. The system controller automatically selects and configures the appropriate ionization chamber for the current treatment modality, enabling a single measurement system to accurately measure both conventional radiotherapy and flash radiotherapy without exchange or recalibration.
Solution Approach 2:
The measurement system incorporates dynamic reconfiguration capabilities where the controller can switch between different ionization chambers and adjust measurement parameters in real-time based on the treatment modality. This dynamic adaptation allows the system to maintain optimal measurement accuracy across varying radiation conditions while eliminating the need for manual intervention or system downtime during modality transitions.
2Measurement precision
If the ionization chamber measurement system is exchanged when switching between treatment modalities, then measurement precision for different modalities is ensured, but time consumption and operational efficiency worsen
Solution Approach 1:
Multiple ionization chambers are pre-configured with different electrode arrangements, active volumes, and measurement parameters optimized for specific treatment modalities before operation begins. The system controller stores pre-configured settings for conventional radiotherapy, flash radiotherapy, and other modalities. When a treatment modality is selected, the controller automatically retrieves and applies the corresponding pre-configured settings, eliminating the need for time-consuming calibration procedures during modality transitions.
3Device complexity
If a single ionization chamber is used for different treatment modalities, then device complexity is reduced, but measurement precision deteriorates due to inability to accommodate different radiation rates
Solution Approach 1:
The measurement system is divided into multiple independent ionization chambers, each with specialized electrode arrangements and active volumes optimized for specific measurement ranges and radiation types. This segmentation allows each chamber to be precisely tuned for particular treatment modalities while maintaining overall system manageability through automated controller selection and configuration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables seamless switching between different radiation therapy modalities without the need for recalibration, improving the availability and efficiency of radiation therapy systems by maintaining accurate measurement of radiation rates and flux across varying treatment modalities.
Implementation Method 1
the ionization chamber measurement system 140 measures the charge from the number of ion pairs (e.g., electron and positively charged atom) created by incident radiation as the particle stream passes through the chamber
Implementation Method 2
the ionization chamber can include two electrodes, a high-voltage source that applies a high-voltage potential between the two electrodes
Data Source
AI summary
An asymmetric dual-mode ionization chamber measurement system can include a first high-voltage plate, a second high-voltage plate and a readout plate. The first high-voltage plate can be disposed from the readout plate by a first active volume. The second high-voltage plate can be disposed from the readout plate by a second active volume. A high-voltage potential can be coupled to the first high-voltage plate during a first mode, and to the second high-voltage plate during a second mode. Ion pairs generated by a radiation stream passing through the first active volume during the first mode and the second active volume during the second mode can be measured at the readout plate to determine a radiation rate of the ionizing radiation. The asymmetric dual-mode ionization chamber measurement system can advantageously measure different radiation streams that have significantly different ranges of radiation rates flux.